1. Technical Field
This invention relates to inflatable refuge structures and, more particularly, to an inflatable portable refuge structure including a generally gas-impervious refuge chamber and an airlock chamber connected to the refuge chamber, an inner resealable entrance between the refuge chamber and airlock chamber and an outer resealable entrance in the airlock chamber, the refuge chamber and airlock chamber being inflated by a continuous source of pressurized air supplied from a remote, uncontaminated fresh air source, the refuge chamber and airlock chamber further including at least one one-way pressure valve to release air from within the chambers in response to increased air pressure within the chambers.
2. Description of the Prior Art
Among the many hazards found in the workplace are immediately dangerous to life and health (IDLH) atmospheres which are encountered in various occupations. Examples of situations in which an IDLH atmosphere may result include but are not limited to:
1) underground construction/mining; PA1 2) confined space work; PA1 3) hazardous material handling; PA1 4) refineries that have accidental releases of toxic gases; PA1 5) waste treatment plants with releases of toxic gases (such as hydrogen sulfide); PA1 6) vehicle tunnels filled with smoke from an automobile accident; and PA1 7) any other occupations where toxic fumes may be encountered.
While many of the above-described locations may or may not include devices such as respirators or the like which provide limited and temporary safety, there is a need for a portable refuge structure which is capable of providing more long-term protection for persons trying to escape IDLH atmospheres.
Two necessary elements for such a portable refuge structure are that the refuge structure be constructed for quick assembly and erection and that the refuge structure be supplied with uncontaminated air so that persons without respirators may breathe normally and those using respirators that expire and no longer provide protection may remove the respirators and breathe normally. Types of structures which may be quickly erected are inflatable enclosures which are supported by air pressure within the enclosure. Such enclosures are disclosed in Joy, U.S. Pat. No. 2,910,994, Wardlaw, III, U.S. Pat. No. 5,101,604, Caminker, et al., U.S. Pat. No. 3,497,606, and Slotnick, U.S. Pat. No. 3,393,479. Without exception, however, these inflatable enclosures are inflated by blowers which draw air from the area surrounding the inflatable enclosure and force the air within the inflatable enclosure. Clearly, if the inflatable enclosure is surrounded by an IDLH atmosphere, it is both dangerous and pointless to inflate the intended refuge enclosure with the same poisonous atmosphere. There is therefore a need for an inflatable enclosure which may be inflated by connection to an externally remote highly pressurized air source which will provide uncontaminated air.
Additionally, it is seen that some sort of inflating apparatus is necessarily included with each of the prior art devices disclosed above, the inflating device having to be carried around with the inflatable enclosure at all times. However, in many instances, the transportation of large blowers or the like is impractical and undesirable. There is therefore a need for an inflatable enclosure which may be inflated by connection to sources of highly pressurized air which are already present in the workplace area.
Furthermore, it is noted that each of the prior art enclosures cited above requires at least eight to ten minutes to inflate to a usable structure. In IDLH atmospheres, exposure of the body for such an extended period of time may prove harmful, even fatal. There is therefore a need for an inflatable portable refuge structure which may be quickly inflated, thus reducing exposure time of the body to the poisonous atmosphere.
Finally, it is noted that of those inflatable enclosures in the prior art which include airlocks, none of them show a single airlock connected to two or more refuge chambers. Such a feature may prove important when quarantine of one group of survivors is necessary. Furthermore, two chambers, one on each side of an airlock chamber, allows the airlock chamber to remain erect without internal or external rigid structural members. Additionally, having two chambers connected to a central airlock reduces contamination levels in any one chamber and allows for quicker fresh air purging from either chamber, instead of higher levels of contamination in one chamber. As a practical matter, in mining and tunnelling operations, standard crew size is 6-8 persons. A mine rescue team would normally include up to 5 persons. Prior art devices cannot provide for quarantine of a contaminated crew from the rescue team. There is therefore a need for such a structure which includes more than one refuge chamber.
Therefore, an object of the present invention is to provide an improved inflatable portable refuge structure.
Another object of the present invention is to provide an inflatable portable refuge structure having at least one refuge chamber to which is connected an airlock chamber, air being supplied to the two chambers by an uncontaminated pressurized air source remotely located from the refuge structure, and the refuge chamber and the airlock chamber further including at least one one-way pressure valve to release air from within the chambers in response to increased air pressure within the chambers and airlock.
Another object of the present invention is to provide an inflatable portable refuge structure which is inflated by connection to standard high pressure compressed air lines commonly found where pneumatic tools are used.
Another object of the present invention is to provide an inflatable portable refuge structure which includes an airlock chamber which is not supported by any rigid structural members.
Another object of the present invention is to provide an inflatable portable refuge structure which will constantly purge air from the interior of the structure through one-way valves in the structure thereby creating a self-purging effect.
Another object of the present invention is to provide an inflatable portable refuge structure which may be easily and quickly transported to a site having an IDLH atmosphere, quickly inflated and be supplied with uncontaminated air from a remote source.
Another object of the present invention is to provide an inflatable portable refuge structure having two or more chambers connected to a single airlock to allow for quarantine of a selected group of survivors or accommodation of a greater number of survivors.
Finally, an object of the present invention is to provide an inflatable portable refuge structure which provides a safe haven for persons needing shelter from an IDLH atmosphere over an extended period of time.